Development of a method for forest cafeteria tests for evaluating chemical deterrents against bark stripping by sika deer (Cervus nippon yesoensis)

Damage caused by sika deer (Cervus nippon yesoensis) is a serious problem in commercial and environmental (non-harvested) forests in Hokkaido, northern Japan. Cafeteria tests in forests may be useful for evaluating the efficacy of chemical deterrents against bark stripping by deer. To develop a method for forest cafeteria tests in the continuous snow cover period, two experiments were carried out. In the experiments, logs were produced from tree trunks, and used as carriers of chemical deterrents. Carriers were installed in forests and fed to deer. The first experiment was to find suitable sites and installation methods for carriers. Criteria for the local suitability and the installation methods were as follows: a) Sites where deer are active should be selected; b) Carriers should be installed along actively used deer trails; c) Installation sites of carriers should be changed in response to deer movement; d) Carriers should be produced from tree species that deer naturally prefer; and e) Each carrier should be partially buried in the snow. The second experiment evaluated the feasibility of a cafeteria test method based on the results of the first experiment. The method was used for 13 sets of the cafeteria test, in which the deterrent effectiveness of 5 chemicals (wood tar, rosin, wood vinegar, and 2 pyroligneous liquors) was examined. We obtained results from all the sets. The chemicals tested did not deter bark stripping by deer. Nevertheless, the method used in the present study was practical for the cafeteria tests.     

Prostaglandins F2α and E2 in rat placenta and fetal membrane: a comprehensive immunohistochemistry of their synthetic enzymes and in vivo tissue levels during normal pregnancy

We determined a comprehensive immunohistochemistry of putative isoforms of enzymes for prostaglandin (PG) F₂α and PGE₂ biosynthesis and these PGs levels in placenta and fetal membrane of normal pregnant rats in vivo. Placenta and fetal membrane showed positive immunoreactions for phospholipase A₂ group 4A, but not group 2A, and cyclooxygenase (COX)-1 rather than COX-2. They showed positive immunoreactions for at least one isoform of each of PGF synthase and PGE synthase with tissue-dependent variations. PGF₂α and PGE₂ levels in both tissues were highest on day 12 and declined and remained low thereafter. Obtained data would be the basic information on the primary PGs synthesis in rat placenta and fetal membrane in normal pregnancy.     

Gonadotropin-releasing hormone stimulation of annexin A5 expression in the thymus of male rats

As gonadotropin-releasing hormone (GnRH) is expressed in the thymus, its direct action on thymic cells, including thymic involution, has been suggested. Annexin A5 (ANXA5), a biomarker of GnRH, was used to determine whether GnRH affects the thymus of male rats. Immunohistochemistry showed positive reactions for ANXA5 in large medullary epithelial cells at 30 days of age, and the expression continued until 180 days of age. Organ culture of thymus pieces was performed to examine the direct action of a GnRH agonist (GnRHa) on the expression of Anxa5 and Gnrh mRNA. Thymus tissues obtained from male rats (40–60 days old) were cut into small pieces (2–3 mm³) and incubated for 3 hr with the GnRHa. The expression levels of Anxa5 and Gnrh mRNA were augmented by the GnRHa. Immunohistochemistry of these tissue fragments showed that ANXA5 expression was enhanced, especially in medullary epithelial cells. These results revealed that GnRH synthesis in the thymus could affect thymic epithelial cells after puberty.     

Significance of Mn and Fe for growth of coastal marine diatom <Emphasis Type="Italic">Thalassiosira weissflogii</Emphasis>

The significance of Mn and Fe for the growth of a coastal marine diatom Thalassiosira weissflogii was investigated by performing culture experiments containing macronutrients with either Mn or Fe, or both. Only the addition of both Mn and Fe induced the highest growth rates and maximal cell yields. Maximal growth was maintained in continuous culture media, which were repeatedly prepared by an inoculation of pre-culture and the addition of both Mn and Fe to the control culture medium containing macronutrients. In particular, it was found that the full growth recovery in Mn-sufficient medium (without added Fe) is accomplished by the addition of Fe even after several days’ incubation. On the contrary, there was no sufficient growth recovery by the addition of Mn after a long incubation time in Fe-sufficient medium but without additional Mn. These results suggest that T. weissflogii in Mn-sufficient waters retains the ability for full physiological recovery for a long time, probably resulting from the decrease in the oxidative stress of phytoplankton by the production of antioxidant enzyme Mn superoxide dismutase during a long incubation period.     

Diversity of fimbrillin among Porphyromonas gulae clinical isolates from Japanese dogs

Porphyromonas gulae, a gram-negative black-pigmented anaerobe, is a pathogen for periodontitis in dogs. An approximately 41-kDa fimbrial subunit protein (FimA) encoded by fimA is regarded as associated with periodontitis. In the present study, the fimA genes of 17 P. gulae strains were sequenced, and classified into two major types. The generation of phylogenetic trees based on the deduced amino acid sequence of FimA of P. gulae strains along with sequences from several strains of Porphyromonas gingivalis, a major cause of human periodontitis, revealed that the two types of FimA (types A and B) of P. gulae were similar to type I FimA and types II and III FimA of P. gingivalis, respectively. A PCR system for classification was established based on differences in the nucleotide sequences of the fimA genes. Analysis of 115 P. gulae-positive oral swab specimens from dogs revealed that 42.6%, 22.6%, and 26.1% of them contained type A, type B, and both type A and B fimA genes, respectively. Experiments with a mouse abscess model demonstrated that the strains with type B fimA caused significantly greater systemic inflammation than those with type A. These results suggest that the FimA proteins of P. gulae are diverse with two major types and that strains with type B fimA could be more virulent.     

Serum cystatin C concentration can be used to evaluate glomerular filtration rate in small dogs

Serum cystatin C levels (CysC) are used in human medicine to document progressive kidney failure. Although CysC are not thought to be useful for the diagnosis of kidney dysfunction in dogs, there has been no specific consideration of body weight as a confounding issue. The aim of this study was to assess that the utility of CysC for the diagnosis of decreased glomerular filtration rate (GFR) in smaller vs. larger dogs. In clinically healthy dogs, serum creatinine (Cre) and CysC correlate directly with body weight; we found that dogs weighing <20 kg had significantly lower CysC than those weighing ≥20 kg (0.27 ± 0.07 vs. 0.34 ± 0.05 mg/l, respectively, P<0.001). In dogs weighing <20 kg, CysC had superior diagnostic accuracy for the detection of mildly decreased plasma iohexol clearance (PCio) (<1.8 ml/min/kg) compared with Cre (sensitivity 100% vs. 80.9% and specificity 100% vs. 85.7%); this was not true for dogs weighing ≥20 kg. Additionally, using a cut-off PCio of <1.8 ml/min/kg, the area under receiver-operating characteristics curve (AUC) of CysC was significantly higher than that of Cre in dogs weighing <20 kg (P<0.05); this was not true for dogs weighing ≥20 kg (P=0.695). In conclusion, CysC is a useful marker for the detection of a mild decreasing GFR compared with Cre in dogs weighing <20 kg.     

The TIR–NBS but not LRR domains of two novel N-like proteins are functionally competent to induce the elicitor p50-dependent hypersensitive response

The tobacco N protein recognizes the helicase domain (p50) of the Tobacco mosaic virus (TMV) replicase as an elicitor and mediates hypersensitive response (HR). We obtained two cDNA clones encoding novel N-like (NL) proteins NL-C26 and NL-B69 from Nicotiana tabacum cv. Samsun NN. NL-C26 and NL-B69 had a Toll-interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat (TIR–NBS–LRR) structure and showed 78% and 73% identities to N, respectively. The NL-C26 and NL-B69 genes were also expressed in N. tabacum cv. Samsun nn, which lacks the N gene. Unlike N, NL-C26 and NL-B69, when coexpressed with p50, failed to induce HR on the sites of agroinfiltration in Samsun nn leaves. However, the elicitor-dependent HR in Samsun nn was induced efficiently by chimeric N proteins with the continuous TIR–NBS domains of NL-C26 and NL-B69. On the other hand, the efficiency of HR induction varied significantly among chimeric N proteins with either of the TIR and NBS domains of the NL proteins. In contrast, chimeras carrying the LRR domains of the NL proteins did not induce HR. Thus, the TIR–NBS domains of NL-C26 and NL-B69 could functionally adapt to the LRR domain of N, which may determine the specificity for the elicitor. We speculate that the NL genes are potential HR-inducing resistance genes for undetermined pathogens other than TMV.     

Phosphorus application reduces N2O emissions from tropical leguminous plantation soil when phosphorus uptake is occurring

We examined the effects of phosphorus (P) fertilization on N₂O emissions from an Acacia mangium plantation in Indonesia. We focused on the roles of microbial and plant root activities using a trenching method to prepare root-excluded and root-including plots. In root-excluded plots, P application did not change the amount of N₂O emissions. By contrast, in root-including plots, P application significantly reduced N₂O emissions (from 71.1?±?20.2 to 19.3?±?5.1 mg N m^?2 106 days^?1). Lower total P, Bray-2 P, and Bio-P (microbial P determined by chloroform fumigation extraction method) contents in the soils of root-including plots as compared to root-excluded plots a few days after P application shows that acacia trees absorbed P fertilizer rapidly. This rapid P uptake probably relieved the P limitation of acacia and might have consistently increased root N uptake. This interpretation is supported by lower inorganic N content in P-applied soils (the average of three sampling times is 8.9 and 11.3 μg N g soil^?1 in P-applied soils and soils without P application, respectively), which in turn decreased N₂O emissions. Our study suggests that P fertilizer suppresses N₂O emissions from tropical leguminous forest plantations.     

Involvement of endogenous vasopressin in high plasma osmolality-induced anorexia via V1 receptor-mediated mechanism

It is known that water deprivation or injection of hypertonic saline induces anorexia. The present study examined the possible involvement of vasopressin in the suppression of food intake during high plasma osmolality. Intraperitoneal injection of vasopressin (20 microg/kg) into male rats significantly suppressed food intake for 1 hr. This anorectic effect of vasopressin was reversed by simultaneous injection of a peptide antagonist for V(1) receptor (40 microg/kg), but not for V(2) receptor (40 microg/kg). Intraperitoneal injection of hypertonic saline (20% NaCl, 2 ml/kg) similarly suppressed food intake for 2 hr, which was associated with a transient increase in plasma vasopressin concentrations. This hypertonic saline-induced suppression of food intake was blocked by a V(1) receptor antagonist. Vasopressin (40 ng/2 microl) directly administered into the third ventricle of the brain also suppressed food intake for 1 hr. These results suggest that vasopressin participates in the suppression of food intake during high plasma osmolality, the action of which is mediated by V(1) receptors in the brain.